Thomas Forrest Kelly is the Morton B. Knafel Professor of Music, specializing in historical musicology at Harvard University. He received his Bachelor's degree from the University of North Carolina at Chapel Hill, after which he spent two years in France on a Fulbright in France studying musicology, chant, and organ. He earned a Ph.D. from Harvard University.

Kelly has taught at Wellesley, Smith, Amherst, and at Oberlin, where he directed the Historical Performance Program and served as acting dean of the conservatory. He was named a Harvard College professor in 2000. His main fields of interest are chant and performance practice. He won the Otto Kinkeldey Award of the American Musicological Society for his book The Beneventan Chant (Cambridge University Press, 1989). Other books include Capturing Music (Norton, 2014); Early Music: A Very Short Introduction (Oxford, 2011); First Nights: Five Musical Premieres (Yale University Press, 2000) and First Nights at the Opera (Yale, 2004). He is a member of the American Academy of Arts and Sciences, an Honorary Citizen of the city of Benevento, and a Chevalier de l'Ordre des Arts et Lettres of the French Republic.